I recently aqcuired a Pelican AR-15 case, it's the same size as the double take-down case except about 6" longer, which is nice if you are taking a couple longer barreled sporting guns, or auto's. It was kinda pricey, but the guns don't move in there, and I think it would survive a fall out of the airplane at altitude, the thing is sturdy. I've flown with it 4 times, and everything was fine.

edit: Wow, just realized that was a very old thread I just resurected. And I had posted on it before.........